Vol. XXII. No. 6.] 



POPULAK SCIENCE NEWS. 



85 



Prartital Cfttmistrp an! tl)e 3lrt«. 



SULPHURIC ACID. 



There is hardlj' a single article of commerce 

 which is essential to so man^- industries, and 

 of which any variation in the supplj' or price 

 is so widely felt, as sulphuric acid. More than 

 four hundred j-ears ago Basil Valentine heated 

 green vitriol, or sulphate of iron, and distilled 

 from it a corrosive, oily liquid, which he called 

 oil of vitriol, a name by which it is popularly 

 known at the present day. This substance 

 was not a true sulphuric acid (H^SO^), but a 

 mixture of that substance with sulphuric an- 

 hydride (SOg) ; the formula of Valentine's oil 

 being 2H2SOi + SO3. This acid, which has 

 been manufactured for many j-ears at Nord- 

 hausen in Saxony, is known as Nordhausen 

 oil of vitriol, or fuming sulphuric acid, from 

 the fumes of sulphuric anhydride which it gives 

 off when exposed to the air. 



The true sulphuric acid has been made by 

 practically the same process since 1 770. Over a 

 hundred thousand tons are now annually con- 

 sumed in Great Britain, and large quantities are 

 exported to other countries. The method of 

 its manufacture is, briefly stated, the oxida- 

 tion of sulphurous anh3-dride, SOg, bj- oxides of 

 nitrogen in the presence of steam. The sul- 

 phurous anhj'dride SOj is oxidized to sulphuric 

 anhjdride SO3, which unites with the water, 

 HjO, to form sulphuric acid, H^SO^. The actual 

 reactions that take place are much more com- 

 plicated than those given above, which only 

 serve to illustrate their general course. 



Sulphurous anhydride — or sulphurous-acid 

 gas, as it is more commonly called — is a gas 

 with an intensely suffocating odor. It is formed 

 whenever an ordinary match is ignited. This 

 is made in the acid works by burning sulphur 

 in a specially constructed furnace. More 

 rarely it is made by roasting iron pyrites or 

 sulphide of iron. In the same furnace is 

 placed a vessel containing a mixture of nitrate 

 of soda and sulphuric acid. This gives off an 

 abundant supply of nitric acid, wliich mixes 

 with the sulphurous anhj-dride and air, and 

 passes through a pipe into a series of large 

 leaden chambers, called converting chambers, 

 containing also water and steam, where the 

 sulphuric acid is formed. As the complicated 

 reactions which take place in these chambers 

 may be of interest to students of chemistry, 

 we give them below, according to the latest 

 authorities : — 



Siilpli, Anhyd. Nitric Acid. Water. .Sulpliurii: Acid. Nitrous Aiiliyd. 

 280, + 2HNO3 + HjO = 'm,80, + NjOa. 



The nitrous anhydride in connection with air, 

 steam, and 80^, forms a crystalline compound, 

 known as crystals of the vitriol chambers. 



NjOa + Oj + HjO + 2S0j = 2(SO, . OH . ONO). 



This crystalline compound is immediately de- 

 composed by steam with production of H.^SO^. 



2(80,. OH. 0X0) + H20 = Nj03 + 2(S0j. OH. OH). 



The N.^03 formed in the last reaction is then 

 ready to oxidize a fresh quantitj- of SO^ ; and 

 so the process is, in theory at least, a continu- 

 ous one. 



The sulphuric acid formed in these leaden 



chambers falls to the floor, whence it is 

 drawn off. The residual gases are passed 

 through a condenser known as Gaj--Lussac's 

 tower, where the oxides of nitrogen are ab- 

 sorbed by a stream of sulphuric acid, and 

 passed once more through the converting 

 chambers. 



The acid as it is drawn from the chambers is 

 quite weak, containing about seventj" per cent 

 of H^SO^ ; and it is further concentrated in 

 shallow leaden pans set over a furnace. After 

 the acid in these pans reaches a certain 

 strength, it begins to attack the lead ; and to 

 obtain the strongest acid, the concentration 

 must be completed in retorts of glass or plati- 

 num. Platinum retorts are much the best for 

 this purpose, but glass is considerably used on 

 account of its cheapness ; a platinum retort 

 costing from ten thousand to fifteen thousand 

 dollars. The result of this last concentration 

 is an acid of a specific gravity of 1.84, con- 

 taining about ninety-eight per cent of H^SO^. 



To enumerate all the uses of sulphuric acid 

 would be to give a list of nearly all known 

 industries. Immense quantities are used in 

 alkali works, in tlie manufacture of fertilizers, 

 the refining of petroleum, and the manufacture 

 of chemicals. When first discovered, the won- 

 derful " oil of sulphur " sold for about seventy- 

 five cents an ounce. The improvements in its 

 manufacture since that time have been such 

 that it can now be purchased in England for 

 two and a half cents per pound. The scien- 

 tific monk Basil Valentine could hardlj- have 

 dreamed, when he first produced a few drops of 

 his oil of vitriol, that he was laying the foun- 

 dation of one of the most important industries 

 that our civilization has developed'. 

 — »— 



[Original in Popular Science Vewa.] 



SOME NOTES ON THE USE OF KEROSENE 



AS A FUEL. 



BY F. L. BARTLETT. 



People have long dreamed of the time wlien coal 

 fires, with the attendant dust, smut, and gas, will 

 have become a thing of the past, and some other 

 and more cleanly method is put to use. In the 

 natural-gas regions all this and more is realized 

 in the use of nature's own product, natural gas. 

 Unfortunately, New England and the Coast States 

 are not blessed with a supply of this cheap fuel. 

 Inventors have looked upon the somewhat seduc- 

 tive fluid, kerosene oil, for a long time as the hope- 

 ful substitute for the ugly coal. There is no end to 

 the number of inventions which have been experi- 

 mented with to obtain a cheap, easy, and perfect 

 combustion of kero.sene. Even were the cost con- 

 siderably greater, people would largely use keiosene 

 for heating-purposes, on account of its freedom from 

 dust and dirt. But, for some reason not easy to 

 understand, all seem to have failed, thus far, to 

 produce a system or apparatus really meritorious 

 and good for burning kerosene in the ordinary 

 grates and stoves. The problem looks easy and 

 simple, but it is not. The writer has had consider- 

 able experience, both with his own inventions and 

 those of others, not only in the common stove, but 

 on a larger scale, under steam-boilers and in metal- 

 lurgic furnaces. The results of these experiments 

 may be of use to otheis; and the object of this paper 

 is to give a brief account of some of the trials made, 

 and to sum up, as nearly as may be, the final con- 

 clusions arrived at, in a comprehensive form. 



Refined petroleum — or, as it is commonly called, 

 " kerosene " — is a hydrocarbon containing eighty- 

 six parts of carbon and fourteen parts of hydrogen. 

 It is wholly and completely combustible under 

 proper conditions, and is exceedingly well adapted 

 to produce either heat or light. That kerosene is 

 a powerful source of heat, is shown by the follow- 

 ing table, giving the units of heat in the combus- 

 tion of different fuels: — 



Units of heat 

 per lb. 



Petroleum 20,363 



Anthracite coal 14,698 



Coke 13,640 



Bituminous coal 14,143 



Thus we find that petroleum has nearly thirty- 

 three per cent more calorific or heating power than 

 the best coal, when compared pound for pound. 



Owing to the rather great excess of carbon in 

 kerosene, it burns under natural conditions with a 

 smoky flame; in other words, it requires n forced 

 draught or blast of air to cause it to burn smoke- 

 less, and to get the full equivalent of its heat: this, 

 as I shall show farther on, is the stumbling-block 

 which inventors have met in attempting to utilize 

 kerosene as a fuel. It requires fifteen pounds of air 

 to completely burn one pound of kerosene ; to supply 

 this enormous amount requires more draught than 

 can be usually obtained in the stoves in ordinary 

 use. In the open air, in bulk, kerosene burns with a 

 smoky flame ; it is only by dividing and subdividing 

 the flame by the introduction of air-currents that it 

 can be made to burn smokeless ; even then the air 

 must be in excess. Every one knows how little is 

 required to render a kerosene lamp a smoking nui- 

 sance. If turned up too high, or if the air inlets 

 become clogged, or the chimney canted, it smokes; 

 if turned too low, it smells: in fact, the wick must 

 be well trimmed and well adjusted, in order to get a 

 full equivalent of heat and light. The greater the 

 amount of air that can be drawn through the lamp 

 chimney, the greater the amount of heat and light 

 given. At the same time, more oil is consumed ; but 

 a higher degree of efficiency is reached by a good 

 draught of air, as regards economy of oil The 

 burning by means of wicks is one method of utiliz- 

 ing kerosene oil; and lately some exceedingly good 

 kerosene stoves have been put on the market, both 

 for cooking and heating. Other methods have 

 been in use, as the " fuel cartridge," air and steam 

 sprays, projection against hot firebricks or against 

 corrugated iron, tube jets, coil jets, and numerous 

 other devices, too many in number to attempt to 

 describe within the limits of one article 



The methods of burning may be divided into two 

 classes, — burning by natural draught, and burning 

 by forced draught. The latter method is the one 

 used almost invariably under steam-boilers; while 

 for household use it is not possible usually to ob- 

 tain power to use forced draughts, consequently 

 ■some method must be used which utilizes the natu- 

 ral draught. The writer has recently made some 

 tests in an ordinary flat top, brick-lined stove, u.sed 

 for heating-purposes, and requiring to heat about 

 eight thousand cubic feet of s|iace. The tests were 

 made with a view of getting at the relative cost of 

 heating by kerosene, u.sing different methods of 

 burning the oil. These tests were crude, and not 

 intended to be absolutely accurate, but sufficiently 

 so to get at the practical facts. Six methods were 

 used; namely, — 



By means of the best form of wick stoves. 



By means of the fuel cartridge 



By means of the air spray. 



By means of the steam spray. 



By oil jets projected against firebrick. 



By perforated pipes. 



Eveiy one knows what the kerosene-oil stove is. 

 The fuel caitridge is simply any iron or fire-clay 



